This invention relates to the coding of objects for identification or transmittal of intelligence relative thereto, and more particularly to a unique three channel, binary coding technique for more reliably and accurately coding and sensing the identification of such articles or transmission of intelligence relative thereto.
In recent years the use of machine readable codes to identify objects or provide pertinent information concerning such objects (such as price, stock numbers and the like) has increased considerably. For example, in many retail establishments, all merchandise is marked with a "bar code," and then a reader or sensing device for decoding such information is provided to clerks at check-out counters. The clerk merely passes the sensing device (reader) past the code, and all of the pertinent information is transmitted into the checkout register. This reduces manual computations, inventory, and the like.
In addition, manufacturing facilities utilize similar coding techniques to identify and maintain production and quality control records with regard to various objects, components, and subcomponents during the manufacturing thereof. Sometimes the object is stationary and the reading device is passed across the bar code. In other situations, the reading device is stationary, and objects bearing some type of code thereon are moved by the reading device. In the latter case, erroneous readings may occur as a result of the object to be identified moving at varying speeds, stopping, or changing direction. Most types of bar codes cannot adapt to such changing conditions.
Most coding techniques utilize a plurality of channels, each of which are provided with some type of indicating means or indicia therein representative of one of two logic states. Generally, the combination of logic states at any one time as one scans across the plurality of channels is directly indicative of a decimal number, a letter, or some other code. Examples of such types of coding techniques are shown and described in U.S. Pat. No. 3,453,419 to Torrey; U.S. Pat. No. 4,148,434 to Lorenzo; and Swiss Patent No. 401,552 to Arsenault et al. Another example of a coding technique is disclosed in IBM Technical Disclosure Bulletin entitled "Photostore Format," Vol. 9, No. 12 (May 1967). Each of these references, however, appear to involve some type of coding technique in which the binary code that appears across the channels at any instant is representative of a decimal number. Each also encounters the aforesaid problem when used in connection with intermittently, erratically, or continuously moving objects.
The present invention, on the other hand, is directed to a unique three channel binary coding technique which overcomes this problem. One of these channels is a timing channel and the other two are coding channels. The coding technique of the present invention adopts a concept in which the determination of whether the binary digit is a ONE or a ZERO is determined by the sequence in which the coding channels change their logical state as the relative movement between the object and reading device occurs, and not by the combination of logical states in which the channels exist at any particular instant. More specifically, the invention then is directed to an apparatus or system for generating coded information in binary form which can be read by a reading means. The code includes a medium applied to the moving object on which a linear strip of coded information is applied. The linear strip of information includes three parallel channels of coded information, one of the channels being a timing channel lying adjacent a first and second coding channel. Each of the channels includes some type of indicating means associated therewith which is representative of one of two logical states, which logical states change at prescribed intervals along the channel. The reading means includes a sensor in the form of a photodetector, mechanical detector, electrical switch contacts, or electrical sensors, for determining separately the logic states from each channel as the linear strip passes thereby. The linear strip is divided into longitudinal segments and subsegments extending across the three channels. The passing of three successive subsegments equals one segment and thus a single bit of binary information. The logic state of said channels in each segment and subsegment are so arranged that the sensing means can determine from the timing channel that a new bit reading is commencing and from the sequence of change in the coding channels whether the bit is a ONE, a ZERO, as well as whether the reading is valid or erroneous.
The coding technique of the present invention is unique in that an object to be identified may move at varying speeds, may stop, or may change direction without causing errors in reading its identification. The three channel code may also be adapted for use in other environments such as signalling, communications, key locks, pass words, card readers, etc., as well as identifying stationary objects.
The three channels are arranged parallel to each other and along the path in which the object to be identified moves. The code is recorded on the three channels in a number of ways, such as by colored markings, opaque and transparent markings, light and dark areas, holes, pins, pegs, or variations in surface shape, or any other means which are capable of representing logically true and false states which may be automatically read by some type of machine reader. The readers may include photodetectors, switch contacts, mechanical readers, or electrical sensors which detect the color, shape, transparency, presence or absence of holes, pegs, pins, or other physical attributes suitably encoded.
In the preferred embodiment, the reader is stationary and reads the codes from the passing object, but it is obvious that the object to be identified could be stationary while the reader is set in motion, or both the reader and the object to be identified could be in motion.
It is therefore an object of the present invention to provide a unique binary coding technique.
It is another object of the present invention to provide a coding technique of the type described which may reliably and accurately identify objects which are moving relative to the reading means.
A further object of the present invention is to provide a coding technique of the type described in which the determination of the identification is made by the order in which logic states change, rather than by the logical condition at an instantaneous point in time or space.